Electrical apparatus



H. E. SOMEs ELECTRICAL APPARATUS Filed Maronl 27, 1942 v INVENTOR`Homard E. So'mes m EL llu Hllllllllllll March 27, 1945.

' ATTORNEY Patented Mar. 27, 1945 ELECTRICAL APPARATUS Howard E. Somes,Detroit, Mich., assignor to Budd Induction Heating, Inc., Philadelphia,Pa., a corporation of Michigan Application March 27, 1942, Serial No.436,413

(Cl. F75-361) 4 Claims.

This invention relates to electrical apparatus, more particularly toimprovements in transformers and the like of the type shown in my UnitedStates Letters Patent No. 2,223,902 dated December 3, 1940.

One of the objects of the present invention is to provide a currentconducting coil having a magnetic circuit element or magnetic core withmeans associated with such element or core in such manner as to dividethe same into a plurality of electrically separated units whereby tomaterially increase the resistance to induced current now and therebyminimize heating effects resulting from such current flow.

Another object is to provide a transformer having annular magneticcircuit elements of lammated magnetic material for one or both of itswindings with non-conductive means for dividing the laminations into aplurality of separated groups whereby to increase the resistance toinduced current ow and minimize heating thereof as a result of suchflow.

Another object is to provide a transformer mechanism with concentricallyarranged primary and secondary elements which are so assembled to asupporting structure as to facilitate disassembly for inspection andrepair.

A further object is to provide such a transformer wherein each of theprimary and secondary elements may be readily and quickly removed fromthe supporting structure without disturbing the position of the other.

With the above and other objects in view, which l from the followingdescription will be readily apparent to those skilled in the art towhich the invention aopertains, the present invention consists incertain features of construction and combinations of parts to behereinafter described with reference to the accompanying drawing andthen claimed,

In the drawing which illustrates a suitable embodiment of the invention,

Figure 1 is a longitudinal section through the transformer in question,and

Figure 2 is a transverse section taken approximately on line 2-2 ofFigure 1.

Referring to the accompanying drawing in which like numerals refer tolike parts throughout the several views, the transformer of the presentinvention embodies a primary element I and a secondary element IIconcentrically arranged within the primary element and circumferentiallyspaced therefrom by a narrow .air gap I2, as in my Patent No. 2,223,902aforesaid.

I'he primary element consists essentially of a primary winding or coilI3 mounted within a recess I4 formed within the inner surface of aprimary magnetic circuit element I5 of annular form. The magneticcircuit element I5 is comprised of a plurality of radial taperedlaminations i6 arranged in annular formation within a surroundingannular shell I'i' having an integral lation through which the terminals24 of the coil I3 extend radially outwardly. Similarly the shell Il isprovided with a longitudinal recess 25 containing an insulation block 26and the terminals 24 likewise extend through the block 26.

The transformer includes a casing 2T surrounding and positively locatingthe' shell l1, which casing is provided with a clamping ring 28 securedto the lower end of the casing by cap screws 29 to abut the shell ringI9. This structure is supported on an annular support 30, cap screws 3|being provided to extend through the clamping ring 28 to threadablysecure the casing 21 to the support 3U, clamping the ring 28therebetween as shown in Figure 1.

The upper end of this structure is closed by an end plate or housing 32,cap screws 33 and 34 being provided to threadably secure the housing 32to the shell I1 and casing 21.

The support is formed with an annular hub portion 35 and an axiallyextending coaxial annular extension 36 which terminates in a radiallyoutwardly extending ilange 31 and a radially inwardly extending ange 38.

The secondary element II, as previously described is arranged coaxiallywithin the primary element I0 and embodies an internal annularsupporting sleeve 39 surrounded by an annular core comprised ofannularly arranged radial tapered laminations 4l! clamped between adovetailing flange 4I at one end of the sleeve 39 and a clamping plate42 at the other end of the sleeve 39, securing bolts 43 extend throughthe clamping plate 42 and the sleeve 39 and are threaded in the hub 35to jointly secure the annularly arranged laminations to the sleeve 39and the sleeve 39 to the support hub 35 vin end abutting engagement.

As in the case of the primary element, the 1ammations it are removedor ashort distance and replaced by a segmental insulating block M, thesupport sleeve 3&3 also being provided with a recess it extendinglongitudinally between but not through its ends.

The secondary winding or coil d@ which is located within a peripheralrecess il in the laminations iid, is illustrated as triple wound and theupper terminals @t thereof are electrically connected to the supportsleeve 39 longitudinally upwardly of the bottom of recess lit.

it will be noted that an annular ring lill having a projecting portionis arranged within the lower end of the support sleeve 39 with theprojecting portion 5@ positioned within the recess or slot This ring d@however is completely insulated from the Walls ci the sleeve 3@ and oithe slot i5 as indicated at tit-and the lower terminals 52 of thesecondary coil it are electrically connected to the projecting portionE@ of ring which is of electrically conductive material. l't is thusseen that the sleeve 39 and ring i9 constitute insulated coaxialconductors for the opposite terminalsoi the secondary coil dit. The ringel@ and sleeve 3@ are electrically connected with concentric conductors53 and 5.1.3. respectively, which conductors are separated by aninsulating sleeve 55. The outer conductor 533 is positioned Within theannular extension 36 of the support Sli and is insulated from theinternal ange d thereof by an insulating sleeve 5d, and is secured inend abutting engagement to the ring t9 by one or more cap screws 51. Theupper end of the conductor 53 is disposed within the insulating sleeve5l and is slidable therefrom. Similarly, the ring @i9 is axiallyslidable from the insulatingsleeve 55. Threadably secured within thesupport sleeve 39 is an annular conductor ring 5t having a number of1ongitudinalextensions or` fingers 59 arranged to have slidableelectrical contact with the end of the inner conductor BQ which projectsaxially beyond the outer conductor.

I have diagrammatically illustrated a heating or inducing coil @il whichis to be energized by tion of the insulating sleeve 55.

The upper end of the outer arbor conductor d3 is provided with a flangedsleeve 65 arranged to have a close sliding electrical contact with theinner wall of the outer conductor 53, and the inner arbor conductor 62is threaded into the interior oi the inner conductor 54 whereby thearbor Si can be readily removed and connected to the transformerconductors. In order to Drevent inadvertent unthreadlngof the arbor 6|it is surrounded by an annular plate 66 which is secured by cap screws'61 to the external flange 31 of the support extension 36 and insulatedfrom the arbor 8| by an insulating sleeve 88. It will be noted that theviiange 69 of the sleeve 65 overlaps the hub of annular plate 66 so thatshould the arbor l6| become inadvertently threaded from the conductor54, the flange B9 will engage the insulation 68 and prevent thel arbor6| from dropping from the apparatus and thus safeguard it from injury.

In order to cool the hollow secondary coil 46 tubular connectors 10 and1|` respectively, connected with conduits 12 and 13 extending through anopening 14 in the end housing 32 are proestacas I vided. lIhe connectorl@ is threaded into the support sleeve til in uid communication with thecoll terminals t8. Similarly, the connector it is threaded to theprojecting portion Si of conductor ring Il@ in uid communication withthe coil terminals 52. The connector l i, however, is surrounded by aninsulating sleeve 15 to insulate it from the support sleeve and endplate 52.

in order to provide access to the threaded connector 58, an end plate orcap l5 is threaded into the annular plate '62, and in order to provideaccess for attachment and removal of the conduits l2 from connectors and1l the end housing 32 is provided with a hand hole 11 which is closed bya removable plate 1d secured to the housing S2 by cap screws 19.

The transformer primary coil terminals 2d are adapted to be connected toa source of current (not shown) and in the case of high power highfrequency current, the currents, induced by the current i'lowing throughthe primary and secondary coils, and flowing through the magneticcircuit elements composed of the laminations i6 and l0 tend to generateconsiderable heat by reason of the induced current flow in thelaminations of magnetic material. In order to reduce the current ow ofthe primary magnetic circuit element i5 and in the magnetic core of thetransformer secondary element, I propose dividing each of these elementsinto a plurality of groups of laminations in such manner as to Yprovidea plurality of induced current paths instead of one path, as has beenthe usual practice. I accomplish this by regularly separating adjacentlaminations by the use of non-magnetic strips, such as for example,mica. These strips are indicated at t@ in the primary element lil and at8| in the secondary element il. Six such strips are illustrated for eachof these elements inv the drawing and by using such mica strips reducedvoltage current is induced in each of the separately insulated coresections. In other words, the current ow in the laminated core isdefinitely reduced by reducing the value of the E. M. F. and breaking itup so that current ilow does not takeplace in a single path. Hence, theresistance to current ow is very materially increased with the resultthat the amount of generated heat is verymaterially reduced. It is to bereadily appreciated, however, that any desired number oi mica strips maybe employed to provide any desired number of current paths. While suchmica strips have been illustrated inY connection with the magneticcircuit or core elements of a transformer, it is to be understood thatthis feature is equally as applicable to any cur'rent device employing amagnetic circuit or core element, such as for example, to the inductionheating head shown in my United States Letters Patent No. 2,256,873,dated September 23, 1941, with equal advantages.

The apparatus described presents many other advantageous features whichfrom the foregoing description, will be obvious to those skilled in theart, including a simplicity of construction which enables easy removalof various parts for inspection, repair and replacement.

It Will be seen that by removing end plate 18 by removal of the capscrews 19 access may be had to the interior of the end housing 32 todisconnect, the connectors 10 and 'Il from the secondary winding 48 andthat by subsequent rement and surrounding casing 21 may be axiallyremoved as a unit together with the end housing 32 from the supportwithout disturbing the secondary element.

On the other hand, after removal of the plate 18 to disconnect theconnectors iti and 'H and the removal of cap screws 33 and 3d, the endhousing 32 may be removed and removal of the secondary element can bereadily occomplished without disturbing the primary element andsurrounding casing by rst removing plate 76, which may, if desired, beomitted entirely, then threading the connector sleeve B outwardly fromsleeve 39, removing cap screws 57 and finally removing the securingbolts 43. The secondary element including its support sleeve 39 can thenbe lifted readily from within the primary element. At this time theconductors 53 and 54 may be removed as a unit by merely removing screwstl land sliding this assembly axially from within the annular extension36.

The divided magnetic core is described and claimed in my copendingdivisional application Serial No. 532,282, filed April 29, 1944.

Inasmuch as various changes may be made in the details and arrangementof the parts, which will be apparent to those skilled in the art,without departing from the spirit and substance of the presentinvention, reference is had. to the appended claims which define thelimits of the invention.

What is claimed is:

1. A transformer comprising a main support, concentric transformerprimary and secondary elements secured to said support, each including awinding, said secondary element being hollow axially and having innerand outer concentric conductors insulated from each other and extendingaxially therewithin, one of said conductors being electrically connectedto one end of said secondary winding and the other conductor beingelectrically connected to the other end of said secondary winding, oneof said conductors having a threaded end portion, an arbor comprisinginner and outer conductors and an insulating sleeve between said lastmentioned conductors, one of said arbor conductors being threadablysecured to said threaded end portion and the other of said arborconductors being slidably engaged with the other of said rst mentionedconductors, said outer arbor conductor having a projection extendingradially outwardly therefrom, and an annular member surrounding .saidarbor and being secured to said support in overlapping relation withsaid projection whereby to prevent said arbor from falling from saidsupport in the event of inadvertent disengagement of said arbor fromsaid first mentioned conductors.

2. A transformer device comprising an annular' main support, concentrictransformer primary and secondary elements secured to one side of saidsupport, each having a winding, inner and outer concentric conductorsinsulated from each other and having electrical connections with thewinding of the inner transformer element, said conductors extendingaxially through said annular support, said support having an integralannular extension extending from the side opposite said transformerelements and surrounding said conductors, said outer conductor beinginsulated from and supported by said extension against lateral movement,and an arbor including inner and outer concentric current conductingelements insulated from each other and naving overlapping electricalcontacts with said inner and Outer conductors, respectively. vone ofsaid inner and cuter conducting elements having a threaded connectionwith the conductor electrically contacted thereby.

3. A transformer device comprising an annular main support, concentrictransformer primary and secondary elements secured to one side of saidsupport, each. having a winding, inner and outer concentric conductorsinsulated from each other and having electrical connections with thewinding of the inner transformer element, said conductors extendingaxially through said annular support, said support having an integralannular extension extending from the side opposite said transformerelements and surrounding said conductors, said outer conductor beinginsulated from and supported by said extension against lateral movement,said outer conductor having an end portion circumferentially spaced fromthe inner conductor and said inner conductor being tubular, and an arborincluding inner and outer current conducting elements insulated fromeach other, said inner element being threaded within the inner conductorin electrical contact therewith and said outer conducting elementextending within said end of said outer conductor in electrical contacttherewith.

4. In a transformer device, an annular main support havingan annularconductor-supporting portion extending from one side thereof, in-

' ner and outer concentric conductors insulated from each other andsupported within and by said extension in coaxial alignment with theopening of said support, the inner conductor at least extending throughsaid opening and projecting axially beyond said outer conductor, anannular member surrounding the projecting end of said inner conductorand having an electrical connection therewith, an annular currentconducting ring within said annular member and surrounding said innerconductor, said ring abutting the end of said outer conductor and beinginsulated from said inner conductor and said annular member, and anannular transformer element carried by said annular member and includinga winding, said winding having a first terminal connection with saidannular member and a. second terminal connection with said annular ring,said second terminal connection extending through and insulated from thewall of said annular member.

HOWARD E. SOMES.

